Optical systems and methods based upon temporal stretching, modulation and recompression of ultrashort pulses

Claim 2

A communication system comprising an ultra-short optical pulse source, pulse stretching means responsive to an ultra-short optical pulse from said source for producing a chirped temporally stretched pulse, modulator means for serially modulating the chirped temporally stretched optical pulse in accordance with predetermined information, and pulse compression means for temporally recompressing the modulated stretched pulse so as to result in a shaped ultra-short optical pulse containing retrievable information in accordance with said modulation.

Claim 3

The communication system recited in claim 1 including a receiver for retrieving the modulated information on the compressed pulse.

Claim 4

The system recited in claim 1 wherein said pulse stretching means and pulse compression means produce chirps which are equal in magnitude but of opposite sign.

Claim 5

The system recited in claim 3 wherein said pulse stretching means comprises a pair of spaced gratings, a pair of spaced lenses having a focal length, f, situated in the pulse path between said gratings, the distance between the grating and lens nearest said grating being less than f and the distance between lenses being 2f, and a mirror to redirect the pulse back through the grating and lens pairs.

Claim 6

The communication system recited in claim 4 wherein said pulse compression means is similar to said pulse stretching means except that the distance between grating and nearest lens is greater than f.

Claim 7

The communication recited in claim 3 wherein said modulator means comprises an electro-optic modulator driven by a programmable signal source.

Claim 8

The communication system recited in claim 1 wherein said pulse source is a mode-locked laser producing pulses in the picosecond to femtosecond range.

Claim 9

The communication system recited in claim 1 wherein said pulse modulator comprises a programmable electro-optic modulator.

Claim 10

The communications system recited in claim 8 wherein said modulator means is driven by a programmable, shaped microwave signal source.

Claim 11

The communication system recited in claim 1 wherein said pulse compression means is selected from dispersion shifted optical fiber, a resonant absorber, single mode fiber, dispersive waveguide and grating-lens arrangement.

Claim 12

The communication system recited in claim 1 wherein said pulse stretching means is selected from the group consisting of single mode optical fiber, dispersion shifted optical fiber, dispersive waveguide and grating-lens arrangement.

Claim 15

The pulse shaping method recited in claim 12 wherein pulse stretching produces a chirped pulse and wherein pulse compression and pulse stretching are equal in magnitude but opposite in sign.

Claim 16

The pulse shaping method recited in claim 13 wherein the temporal changes to the initial pulse are achieved by means of a dual grating/lens system.

Claim 17

The pulse shaping method recited in claim 14 wherein said modulation is electro-optic modulation driven by a programmably shaped microwave signal source.

Claim 18

A synchronous code division multiple access communication system comprising a source of ultra-short optical pulses, a plurality of transmitters, a plurality of receivers and coupling means for coupling said transmitters with said receivers, CHARACTERIZED IN THAT (a) said transmitters comprise temporal pulse stretching means which stretches said ultra-short optical pulses and chirps said pulses, and high-speed phase modulator means for serially encoding said chirped pulses in accordance with predetermined information; and (b) said receivers comprise decoder means including a high-speed phase modulator which is equal and opposite to a particular transmitter modulator code, temporal pulse compression means for reforming said ultra-short optical pulse, and a threshold detector for discriminating between pulses wherein the phase shift impressed upon the pulse at the transmitter is negated in the decoder of the receiver from those that are merely modified at the receiver.

Claim 19

A synchronous code division multiple access communication system comprising a source of ultra-short optical pulses, a plurality of transmitters, a plurality of receivers and coupling means for coupling said transmitters with said receivers, CHARACTERIZED IN THAT (a) said transmitters comprise temporal pulse stretching means which stretches said ultra-short optical pulses and chirps said pulses, and high-speed phase modulator means for serially encoding said chirped pulses in accordance with predetermined information; and (b) said receivers comprise decoder means including a high-speed phase modulator which is equal and opposite to a particular transmitter modulator code, temporal pulse compression means for reforming said ultra-short optical pulse, and a threshold detector for discriminating between pulses wherein the phase shift impressed upon the pulse at the transmitter is negated in the decoder of the receiver from those that are merely modified at the receiver.

Claim 20

The communicating system recited in claim 16 including temporal pulse compressor means in said transmitters for temporally compressing said chirped, encoded pulses; and temporal pulse stretching means in the front end of each receiver for temporally stretching the compressed encoded ultra-short pulses from the transmitter, prior to decoding said pulse.

Claim 23

The method recited in claim 18 wherein encoding is accomplished by high-speed programmable phase modulation.

Claim 24

The method recited in claim 18 including the step of amplifying said stretched pulse.

Claim 25

The method recited in claim 18 wherein an optical threshold detector is employed for discriminating between pulses.

Claim 26

The method recited in claim 18 including the steps of temporally compressing the encoded pulse from said transmitters and subsequently temporally stretching said pulse before decoding in said receivers.